The information on the displacement of buoys in the Traverse du Nord was available to the pilot and to the navigation personnel. The statements and comments of the navigation personnel indicate that, at the time of the occurrence, they were not aware, or had forgotten, that buoy K108 was displaced. The navigation personnel and the pilot stated that the vessel had passed some 23 m from buoy K108, but the buoy was displaced 45 m outside the charted channel. The vessel was, therefore, completely outside the charted channel. As the underkeel clearance was decreasing as the ALGOLAKE moved forward, the vessel soon ran aground.Analysis The information on the displacement of buoys in the Traverse du Nord was available to the pilot and to the navigation personnel. The statements and comments of the navigation personnel indicate that, at the time of the occurrence, they were not aware, or had forgotten, that buoy K108 was displaced. The navigation personnel and the pilot stated that the vessel had passed some 23 m from buoy K108, but the buoy was displaced 45 m outside the charted channel. The vessel was, therefore, completely outside the charted channel. As the underkeel clearance was decreasing as the ALGOLAKE moved forward, the vessel soon ran aground. The navigation personnel of the ALGOLAKE planned to keep close to the northern limit of the channel. The ordered course remained unchanged until the vessel came to a standstill. Buoy K108 was displaced 45m outside the channel since 20July 1994. The vessel's personnel was unaware that buoy K108 was displaced. The vessel's pilot was unaware, or had forgotten, that buoy K108 was displaced. The vessel passed some 23m from buoy K108. The vessel ran aground outside the channel.Findings The navigation personnel of the ALGOLAKE planned to keep close to the northern limit of the channel. The ordered course remained unchanged until the vessel came to a standstill. Buoy K108 was displaced 45m outside the channel since 20July 1994. The vessel's personnel was unaware that buoy K108 was displaced. The vessel's pilot was unaware, or had forgotten, that buoy K108 was displaced. The vessel passed some 23m from buoy K108. The vessel ran aground outside the channel. The ALGOLAKE ran aground north of the Traverse du Nord channel because the pilot and the crew were unaware, or had forgotten, that buoy K108 had been displaced 45 m outside the channel for dredging operations.Causes The ALGOLAKE ran aground north of the Traverse du Nord channel because the pilot and the crew were unaware, or had forgotten, that buoy K108 had been displaced 45 m outside the channel for dredging operations.